Volder first proposed a CORDIC algorithm to utilize hardware implementation for evaluating trigonometric functions in fixed point arithmetic. The CORDIC computing technique typically utilizes a special arithmetic unit for implementing a prescribed sequence of conditional additions or subtractions for evaluating trigonometric functions.
Walther, in A Unified Algorithm for Elementary Functions, Spring Joint Computer Conference, 1971 describes a generalization of the CORDIC algorithm typically for fixed point arithmetic implementation, and typically implemented in hardware due to dilatory execution when implemented in software.
Utilization of the CORDIC algorithm generally may not be feasible in some hardware systems, and software implementation of the CORDIC algorithm generally provides slow evaluation of trigonometric functions. Thus, an efficient floating point trigonometric function evaluator is needed.